The technique of representing a continuous tone image by use of black and white levels only, so that the eye perceives a gray image, is known as "halftone". This technique is used extensively in newspaper reproduction of photographs, for example, whereby the representation of an image with actual levels of gray would be very difficult and expensive. Because a newspaper comprises a two-level graphic representation of information, that is, there is either ink on the page or there is no ink on the page, the prior art has extensively disclosed the halftoning technique whereby a photograph, for example, can be represented by various size dots which when viewed by the eye, is seen as a gray scale photograph. That is, the human eye, being a natural integrator, integrates the various size dots into an interpreted continuous gray scale, if such was present on the original photograph.
Many techniques have been developed in the art for generation and processing of halftone images. Improvements in the prior art are always sought because of budget considerations, accuracy of representation, etc.